It depends on what you regard as high.. my friend who also does Standard (we have such a small school that we don't have the option.. grr..) got a UAI of 92.65.
yeh exactly depends wat u regard as high uai, even with mark of 79 in standard i got uai of 92 but as they say only 1.1% or something got band 5 so that mark of 79 most probably would have scaled me up and probably helped my uai.
In 2002 the highest English Standard mark was 88 and in 2001 it was 87.4
This info is from the UAC scaling page which has the highest mark achieved in each course.